Regrarding Copyright, can you use Youtube Videos in E-Learning Modules

I'm currently developing an eLearning program for a client. It's a for-profit class. There are loads of youtube videos I'd love to use from National Geographic, etc. but am quite certain they wouldn't allow their videos to be used for a for-profit program without being amply compensated. 

With other videos from non-mega entities, I've found it difficult to find contact information. And when I do find them and request permission, I rarely hear back from them. 

So then the onus is for me and the client to create new videos and images, which is a massive time suck and outrageously expensive.  

I understand receiving permission from the owner of the image or video, then crediting said person in the program, but the process is exhausting!